Ceramic heaters are known as heaters for use in, for example, a vehicle-mounted heating system, an oil fan heater, or a glow plug of an automotive engine. For example, in Japanese Unexamined Patent Publication JP-A 2000-156275 (hereafter referred to as “Patent Literature 1”), there is disclosed an example of the ceramic heaters.
The ceramic heater disclosed in Patent Literature 1 comprises: a ceramic structure; a heat-generating resistor embedded in the ceramic structure; and a feeder line embedded in the ceramic structure so as to be connected to the heat-generating resistor.
However, in the ceramic heater disclosed in Patent Literature 1, the possibility arises that due to repeated use in a high-temperature environment the feeder line will be subject to cracking or the like. This causes changes in the resistance value of the feeder line, which may lead to localized unusual heat generation. As a consequence, it is difficult to achieve an improvement in long-term reliability for the case of using the ceramic heater repeatedly in a high-temperature environment.